Pressure control valve and coupling

ABSTRACT

This disclosure relates to a hydrant coupling device including a pressure control valve which, due to its portability, may be connected to any one of a plurality of hydrants to regulate the flow of liquid therefrom, and additionally including a pit valve which is interlocked with the pressure control valve body to prevent the spilling of liquid if the control valve is accidentally forced loose from the pit valve.

RELATED APPLICATION

This application is a division of copending application Ser. No.344,858, filed Mar. 26, 1973, and now abandoned, entitled PressureControl Valve and Coupling, which is a continuation-in-part of copendingapplication Ser. No. 291,894, filed Sept. 25, 1972, entitled PressureControl Valve and Coupling, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to pressure control valves, and more particularlyto a pressure control valve adaptable for use in a hydrant-type fuelingsystem for aircraft or for any other fluid pressure system in which itis desired to automatically regulate the pressure of fluid supplied fromone part of the system to another.

It has been common, particularly in aircraft fueling systems to includein the fluid pressure system, as at an airport, a plurality of stationsat which fluid may be withdrawn, such stations located for example, atparking places where aircraft may be fueled. Each of these stations istypically connected by an underground piping system to a fluid supplytank and a pump which maintains fluid pressure in the entire system.Each of the fueling stations at an airport typically includes a hydrantand a pressure control valve bolted or otherwise semi-permanentlyaffixed to the hydrant. A flexible hose may be coupled between thepressure control valve and the fuel tank of an aircraft. Suchinstallations typically include the pressure control valve below thepavement surface in a pit which may be covered to prevent damage to thepressure control valve. Such installations require an individualpressure control valve for each such pit. However, since it is common touse only a portion of the fueling stations at any given time, the use ofa pressure control valve permanently installed at each pit substantiallyincreases the cost of such installations. In addition, removal of thepressure control valve for maintenance requires that the individualfueling station to which the valve is attached be shut down for a periodof time while the pressure regulator valve is removed from the hydrantand repaired.

Pressure control is a particular problem in re-fueling large airplanesbecause of the tremendous quantities of fuel which must be supplied in ashort period of time. For example, a large jet passenger plane mightrequire 45,000 gallons of fuel to be supplied at flow rates up to 2000gallons per minute at pressures up to 50 psig. The receiving tanks onthe aircraft could be damaged by pressure beyond their designcapability, so it is essential that the pressure be maintainedaccurately within a specified range in order to achieve the desired flowrate while avoiding any possible damage to the aircraft. Moreover,safeguards must be provided to immediately shut the flow off if the hoseto the aircraft ruptures in order to prevent spilling large quantitiesof fuel on the ground. Such spillage at the high flow rates hereinvolved would create a very dangerous condition.

SUMMARY OF THE INVENTION

The present invention alleviates many of the problems of such prior artinstallations by incorporating the pressure control valve in a portableunit which is coupled to the filling hose and may be moved from hydrantto hydrant. In a typical installation it is only necessary to includeenough pressure control valves for peak use of the entire hydrantsystem, which is typically fewer valves than would be required if anindividual valve was attached to each hydrant. In addition, since thepressure control valves are a part of the removable and portable portionof the fluid pressure system, they may be readily replaced by anotherpressure control valve for maintenance purposes, thus avoiding costlydowntime of any one of the filling stations.

In practice it has been found that portable hose connections of anaircraft refueling system are subjected to severe abuse in handling bythe crews. In order to make the pressure control valve of the presentinvention portable without sacrificing reliability it has been foundadvantageous to locate the sensitive control elements thereof within themain body of the pressure control valve where they are not readilysubject to abuse during handling of the valve. In addition, it has beenfound necessary to develop an improved coupling device for attaching thepressure control valve to any one of the fuel hydrants. This couplingmechanism includes a pressure relief valve for relieving the fluid lockwhich would otherwise exist between the hydrant and the pressure controlvalve and would prohibit proper uncoupling of the pressure control valvefrom the hydrant.

In order to facilitate attachment of the pressure control valve to thehydrant, it has been found advantageous to place the pressure regulatorvalve above the surface of the surrounding pavement. However, thisprojection of the valve subjects it to damage from trucks and aircraftmoving on the pavement surface. In order to assure that damage to thepressure control valve does not result in dangerous spilling of fuelfrom the hydrant an improved coupling is used to attach the pressureregulator valve to the hydrant. This coupling includes a mechanical fuseto assure that, if the pressure control valve is struck a sufficientblow to damage the valve or the hydrant, the coupling will release fromthe hydrant. In addition, a spring loaded flapper valve is installed inthe hydrant and is mechanically interlocked to the coupling so that, ifthe pressure control valve is jarred from the hydrant, the flapper valvewill automatically close to prevent fuel from being pumped onto thepavement. The flapper valve includes a pressure equalizing valve tofacilitate opening of the flapper valve against hydrant pressure.

The coupling is additionally interlocked with a poppet valve which isused to close the inlet of the pressure control valve. This interlockprevents the coupling from being removed from the hydrant when thepoppet valve is open to avoid accidental fuel spillage due toinadvertent disconnection of the pressure control valve from thehydrant. The interlock also prevents the poppet valve from being openeduntil the coupling is properly attached to the hydrant.

As an additional safety feature, the coupling remains sealed to thehydrant when the poppet valves are closed. Therefore, in the event of afaulty valve upstream from the coupler, the pressure exerted by thefluid against the pressure control valve prohibits uncoupling of thepressure control valve from the hydrant.

The pressure control valve also includes an excess flow control sensingmechanism which closes the valve if a predetermined rate of flow offluid through the valve is exceeded. In the preferred embodiment, thisexcess flow control may be readily set to close the pressure regulatorvalve at either of two flow levels. This excess flow control is likewiseinterlocked to the improved coupling mechanism so that each time thepressure control valve is removed from a hydrant and replaced on asecond hydrant, the excess flow control is automatically reset to closethe pressure regulator valve at the lower of the two permissible flowrates. The excess flow control must then be manually reset after thepressure regulator valve is coupled to the hydrant if the higher excessflow control setting is desired. This improvement prohibits inadvertentsetting of the excess flow control at the higher flow position.

The coupler of the present invention is spring loaded to enableconvenient connection of the fluid pressure line to the hydrant, so thatthe connection may be made by one operator regardless of the orientationof the hydrant.

Other features of this invention will be apparent from the followingdescription and from the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the pressure control valve positionedabove a hydrant pit prior to coupling of the valve to the hydrant.

FIG. 2 is a schematic sectional view of the hydrant, pressure controlvalve, excess flow control and the coupler which is used to connect thepressure control valve to the hydrant. The excess flow control in FIG. 2has been relocated from its normal attachment position on the pressurecontrol valve to facilitate the description of its operation. In FIG. 2the main piston of the pressure control valve is shown in a partiallyopen position, the pressure control valve is fully coupled to thehydrant, and the excess flow control is in the low flow position.

FIG. 3 is a schematic sectional view similar to FIG. 2 showing theconfiguration of the pressure control valve and hydrant subsequent tocoupling these elements together, but prior to opening of either of thepoppet valves or the main pressure control piston.

FIG. 4 is an enlarged schematic sectional view of a portion of thecoupling mechanism and hydrant shown in FIGS. 2 and 3. In FIG. 4, thecoupling mechanism is shown in the configuration of FIG. 1, that is,prior to coupling of the valve to the hydrant.

FIG. 5 is a schematic sectional view taken along line 5--5 of FIG. 2.

FIG. 6 is a schematic sectional view taken along line 6--6 of FIG. 5.

FIG. 7 is a schematic sectional view taken along line 7--7 of FIG. 6.

FIG. 8 is a schematic sectional view taken along line 8--8 of FIG. 6.

FIG. 9 is a schematic sectional view, taken along line 9--9 of FIG. 2,but with the flapper valve in a closed position.

FIG. 10 is an elevation view, partially cut away, showing the wheelassembly used to transport the pressure control valve.

FIG. 11 is a partial schematic view, partially in section, similar toFIGS. 2 and 3, showing an improved spring-biased coupling mechanism.

FIG. 12 is a partial schematic view, partially in section, similar toFIG. 11, but rotated 90° about the vertical axis from the view of FIG.11, showing the improved spring-biased coupling mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring initially to FIG. 1, the pressure control valve main housing11 is shown connected to a flexible hose 13 which, in a typicalinstallation, leads to an aircraft fuel tank (not shown) to be filled.The hose 13 is typically attached, at spaced intervals wheeled dollies(not shown) to facilitate transporation of the hose 13. The main housing11 is rigidly connected, as by flanges, to a coupler 15 which isdesigned to engage an American Petroleum Institute type hydrant pitvalve 17.

As shown in FIG. 1, the pit valve 17 is advantageously located below thesurface of the surrounding pavement 19 so that it may be covered toprotect it when not in use. The pressure control valve 11, however,typically extends above the pavement 19 when coupled to the pit valve17, so that the hose 13 may lie along the surface of the pavement 19during use. A pair of wheels 21 is mounted on the pressure control valve11 to facilitate rolling the pressure control valve 11 and hose 13 tothe pit valve 17.

Referring to FIGS. 2-9, the functional details of the pressure controlvalve 11, the coupler 15 and the pit valve 17 may be explained. Thepressure control valve 11 includes a main flow passage, having an inlet27 and an outlet 29, the orifice of which may be adjusted by a mainpiston 31 to regulate the flow of liquid through the valve 11. The mainpiston 31 includes a piston actuating chamber 33 which may bepressurized, as explained below, to adjust the position of the mainpiston 31. This chamber is sealed, as by an O-ring 35, to a cylindricalbore 37 which forms a portion of the housing of the pressure controlvalve 11. The chamber 33 is additionally sealed by an O-ring 39 to theouter cylindrical surface of a tubular member 41 which is attached tothe housing of the valve 11. The piston 31 is therefore free to moveaxially along the tubular member 41 and the cylindrical bore 37, whilethe actuating chamber 33 remains sealed from the main flow passage. Amain piston seal 43 (See FIG. 3) contacts a main piston seat 45 when themain piston 31 is at its closed position, thereby closing off the mainflow passage. A spring 47 bears against a portion 48 of the piston and aportion 49 of the body of the valve 11 and biases the main piston 31 toa closed position.

Operation of the pressure control valve is best described in referenceto FIG. 3. Pressure within the chamber 33 is regulated in order toadjust the axial position of the main piston 31. High pressure fluidfrom the hydrant is admitted through a passage 51 to a pilot supplyorifice 53 which controls the rate of fluid flow into a control passage55. Fluid in this controlled passage 55 is allowed to flow to the mainflow passage outlet 29 of the pressure control valve 11 through thetubular member 41 under the control of a pilot valve 57. The relativerate of fluid flow into the control passage 55 through the orifice 53and out of the control passage 55 under the control of the pilot valve57 regulates the pressure in the control passage 55. A piston dampingorifice 59 allows fluid to flow between the control passage 55 and theactuating chamber 33 at a controlled rate. A change in pressure in thecontrol passage 55 will therefore change the axial position of the mainpiston 31, but the rate at which the main piston 31 may be moved iscontrolled by the size of the orifice 59.

A second orifice 61 connects the control passage 55 to the actuatingchamber 33. The size of this orifice 61 is controlled by a needle valve63 which is biased to close the orifice 61 by a spring 65 which bearsagainst the body of the valve 11. The position of the needle valve 63 iscontrolled by the main piston 31. When the main piston 31 is closed to agreater extent than that shown in FIG. 2, the needle valve 63 is closedand flow of fluid between the control passage 55 and the actuatingchamber 33 is controlled by the orifice 59. When the main piston isopened to a greater extent than shown in FIG. 2, the main piston 31contacts the stem of the needle valve 63 and raises the needle valve 63from its seat, thereby partially opening the orifice 61. Since the sizeof the orifice connecting the control passage 55 to the piston actuatingchamber 33 controls the rate at which changes in pressure in the controlpassage 55 can affect a change in the position of the main piston 31,the main piston 31 may be adjusted at a faster rate when the needlevalve 63 is open. Since rapid fluctuation in the position of the mainpiston 31 when the main piston 31 is only slightly open would causeextreme pressure fluctuations at the outlet 29 of the valve 11, theorifice 59 is designed to limit the short term fluctuations at thisposition of the main piston 31. However, when the main piston 31 isopened to a significant extent, so that a large quantity of fluid isflowing through the pressure regulating valve 11, it is desirable toallow the main piston 31 to regulate the flow more rapidly. The needlevalve 63 therefore adjusts the possible rate of flow between the controlpassage 55 and the piston actuating chamber 33 in accordance with theposition of the main piston 31.

In order to maintain the pressure at the coupling (not shown) betweenthe hose 13 and the aircraft tank at the proper level, a pressuresensing tube 67 is connected to the hose 13 at the extremity adjacent tothe aircraft tank and this pressure is conducted through a passage 69 toone side of a pressure sensing diaphram 71 which is attached to thepilot valve 57. This diaphram 71 is biased toward a position whichcloses the pilot valve 57 by a spring 73.

Air under regulated pressure is supplied to the other side of thediaghram 71 through a passage 75. The pressure of the air in passage 75is adjusted to maintain the proper pressure at the aircraft fuel tank.It will therefore be understood that when the air pressure in thepassage 75 exceeds the pressure in the passage 69 and the force of thespring 73, indicating that the pressure at the fuel tank is too low, thediaphram 71 will move against the bias of the spring 73 to open thepilot valve 57, increasing the flow of fluid from the control passage 55into the outlet 29 of the valve 11, thus reducing the pressure in thecontrol passage 55. As this pressure is reduced, fuel will flow from thepiston actuating chamber 33 through the orifice 59 (and the orifice 61if valve 63 is open) into the control passage 55, thus allowing the mainpiston 31 to move away from its seat 39, thereby opening the valve 11and increasing the downstream pressure. If, on the other hand, thepressure at the fuel tank and in the passage 69, along with the bias ofthe spring 73, exceeds the air pressure in the passage 75, indicatingthat the downstream pressure is too high, the diaphram 71 will move toclose the pilot valve 57 so that the flow of fluid into the controlpassage 55 through the orifice 53 exceeds the flow through the pilotvalve 57, increasing the pressure in the control passage 55 and, throughthe orifice 59 (and the orifice 61, if open) increasing the pressure inthe actuating chamber 33 to move the main piston 31 toward its closedposition, reducing the downstream pressure.

A high capacity pilot valve 77 is included in the pressure control valve11 to bypass the control passage 55 to abruptly close the main piston 31in the event that the pressure at the aircraft tank increases abruptly.This abrupt increase in pressure at the tank may occur, for example,when the tank is full and the valves within the tank close. The valveseat 79 of the pilot valve 57 is integral with the valve 77 whichincludes a sealing lip 81 which closes a port 83 between the highpressure passage 51 and the piston chamber 33. This valve 77, which isbiased by a spring 85 to close the port 83, (See FIG. 3) is opened bymotion of the pilot valve 57 after the pilot valve 57 has contacted itsseat 79. The tension of the spring 73 is selected to exceed the tensionof the spring 85 so that the high capacity pilot valve is open wheneverair pressure is not applied to the passage 75. If the pressure at thetank, as monitored by the pressure sensing tube 67, exceeds the airpressure in the passage 75, the diaphram 71 will move the pilot valve 57into contact with the seat 79 and will continue moving the pilot valve57, the seat 79 and its associated high capacity valve 77 so that theport 83 allows flow of the high pressure hydrant fluid directly from thepassage 55 into the piston actuating chamber 33 which will immediatelyclose the main piston 31. Thus, any large increase in the downstreampressure or reduction in the air pressure will affect an immediateclosing of the pressure control valve 11 to avoid damage or rupture todownstream houses and tanks. A passage 87 connects between the two facesof the high capacity pilot valve 77 to avoid a fluid lock behind thepilot valve 77 which would otherwise prohibit its motion. This passage87 likewise equalizes the pressure on the opposite faces of the highcapacity pilot valve 77 so that its operation is not affected by changesin hydrant pressure.

From the foregoing, it can be seen that the control components of thepressure control valve 11, that is, the pilot valve 57 with itsassociated diaphram 71, passages and orifices 55, 69, 75, 59, 61 and 53are housed within the main body of the pressure control valve 11 toprotect the elements from abuse during use and transporation of thepressure control valve 11. In addition, the entire pressure controlvalve 11 is constructed in the form of an elbow, with the outlet 29being positioned at right angles to the inlet 27. This constructionfacilitates the connection and disconnection of the valve 11 from thehydrant 17 since the hose 13 may be laid flat along the pavement 19, andpermits access to the control components for maintenance purposes.

The pressure control valve 11 additionally incorporates an excess flowcontrol 89, best shown in FIGS. 2 and 3, which operates to relieve theair pressure in the passage 75 in the event that the fluid flow ratethrough the valve 11 exceeds a predetermined maximum. As will be readilyunderstood, if the hose 13 is ruptured or becomes disconnected from thefuel tank which is being filled, the downstream pressure will be greatlyreduced. Since a downstream pressure reduction will cause the mainpiston 31 to open to an even greater extent, a great quantity of fuelmay be spilled on the pavement. The excess flow control 89 is used toconnect the source of regulated air pressure, which is connected to aconduit 91 to the passage 61. The conduit 91 leads to a passage 93 whichopens into a bore 95 in the body of the excess flow controller 89. Avalve 97 is axially moveable within the bore 95 and includes a reduceddiameter portion 99 between a pair of O-rings 101 which seal the valve97 within the bore 95. With the valve 97 at the lower extreme of itsaxial movement, as shown in FIG. 3, the reduced diameter portion 99connects the passage 93 to the passage 75 and allows the regulated airpressure to pass from the conduit 91 into the passage 75 to control theposition of the pilot valve 57. When the valve 81 is at the upperextreme of its axial travel, the passage 93 is blocked, and the passage75 is vented through a passage 103 within the valve 97 to theatmosphere. Therefore, with the valve 97 at this latter extremity in itsaxial travel, the air pressure within the passage 75 is exhausted andthe diaphram 71 under the bias of the spring 73 will operate to closethe pilot valve 57 and to open the high capacity pilot valve 77, causingthe main piston 31 to close. The valve 97 is biased by a spring 105 tothis latter position wherein the pressure within the passage 75 isexhausted, but is maintained at the other extremity to allow pressurizedair to flow from the passage 93 to the passage 75 by the interference ofa pin 107 which is connected to a piston 109. This piston 109 is biasedby a spring 111 to a position which maintains the pin 107 against thevalve 97. A reduced diameter portion 113 in the valve 97 accepts the pin107 to hold the valve 97 in its normal operating position.

A pitot-static tube 115 monitors the dynamic and static pressure withinthe pressure regulating valve 11, and, through a pair of conduits 117and 119, controls the position of the piston 109. The conduit 117connects the static pressure portion of the pitot-static tube 115 to oneside of the piston 109, while the conduit 119 connects the dynamicpressure portion of the pitot-static tube 115 to the other face of thepiston 109. So long as the dynamic pressure does not exceed the staticpressure by a predetermined amount, the spring 111 will maintain thepiston 109 at the extremity shown in FIG. 3, with the pin 107 positionedwithin the reduced diameter portion 113 of the valve 97. If, however,the flow within the valve 11 becomes excessive, the dynamic pressurewill exceed the static pressure by an amount sufficient to overcome thetension of the spring 111 and the piston 109 will move the pin 107 outof engagement with the valve 97. The spring 105 will then drive thevalve 97 to its other extremity, exhausting the passage 75 and closingthe main valve 31.

In order to re-initiate fluid flow through the valve 11, the end 121 ofthe valve 97 must be depressed by the operator to align the pin 107 withthe reduced diameter portion 113, cocking the valve 97. The rate of flowat which the dynamic pressure exceeds the static pressure by an amountsufficient to move the piston 109 is determined by the tension in thespring 111. This tension is determined by the position of a flange 123which secures the other extremity of the spring 111. This flange 123 issupported by a rod 125 which is axially moveable within a bore 127 inthe excess flow control 89. Due to the tension of the spring 111, theflange 123 and rod 125 will normally be maintained at a first positionwith an enlarged diameter portion 129 of the rod 125 abutted against thebore 127. If, however, a button 131, connected to the rod 125, isdepressed by the operator, the rod 125 and the flange 123 may be movedto increase the tension in the spring 111. The button 131 includes anaperture 133 which will accept a pin 135. The pin 135 is biased by aspring 137 toward the aperture 133. If, therefore, the operatordepresses the button 131, the pin 135 will engage the aperture 133, andthe tension in the spring 111 will be increased to require a greaterdifferential between the static and dynamic pressure monitored by thepitot-static tube 115 for movement of the pin 107 out of engagement withthe valve 97. With the button 131 so depressed, the pressure controlvalve 11 is in a high flow configuration allowing a higher flow ratebefore the valve 97 moves to cause a closing of the main piston 31.

The spring 137 is maintained within a cup shaped member 139 which isaxially moveable within a sleeve 141 and biased by a spring 143 againsta cam 145. The spring 143 is selected to have a tension which exceedsthat of the spring 137. This cam 145 is included on a main lever 147which is used to open a poppet valve 149 of the pressure control valve11. Since the entire excess flow control 89 has been positioned in thefigures for ease of illustration, rather than in its actual position,the cam 145 is shown separated from the main lever 147. When the mainlever 147 is turned to a position, as shown in FIG. 3, which closes thepoppet valve 149, the cam 145 is turned to allow the cup shaped member139 to move axially away from the button 131. An annular flange 151 onthe member 139 engages an enlarged diameter portion 153 of the pin 135when the cam 145 is turned to the position shown in FIG. 3. Thisengagement of the annular flange 151 with the pin 135 withdraws the pin135 from the aperture 133 allowing the button 131 to move axially due tothe bias of the spring 111 to the low flow position. However, when thehandle 147 is turned to open the poppet valve 149, as shown in FIG. 2,the annular flange 151 becomes disengaged from the enlarged diameterportion 153 of the pin 135, and the pin 135 is biased against the faceof the button 131 by the spring 137. In this position of the cam 145, ifthe button 131 is depressed by the operator, the pin 135 will engage inthe aperture 133 and maintain the excess flow control 89 in the highflow position. The action of the cam 145 therefore provides a safetyfeature which automatically withdraws the pin 135 from the aperture 133and allows the excess flow control 89 to return to the low flow positionevery time the pressure regulator valve 11 is disconnected from onehydrant and connected to another, since this operation requires rotationof the main lever 147.

The pressure control valve 11 is connected to the hydrant pit valve 17by means of a coupler 15, best shown in FIGS. 3, 4, 7 and 8, which isrigidly attached to the valve 11. The coupler 15 includes a collar 155which is axially slideable along an enlarged diameter portion 157 at thelower extremity of the coupler 15. An annular flange 159 of the collar155 engages a series of lugs 161, each of which is pivotally connectedby a pin 163 to the enlarged diameter portion 157 of the coupler 15.These lugs 161 are designed to latch the coupler 15 to a standard APIhydrant pit valve flange 165 and are held in latching position by theannular flange 159, as shown in FIG. 3. The lugs 161 include aprotrusion 167 which is engaged by the annular flange 159 when thecollar 155 is raised to the position shown in FIG. 4 to rotate the lugs161 about the pins 163 to release the coupler 15 from the flange 165.The lugs 161 are preferably constructed of a proper size and material sothat they will rupture if the pressure control valve 11 is torn from thepit valve 17. This intentional mechanical failure of the lugs 161operates as a mechanical fuse to protect the pit valve 17 from thedamage which might be caused, for example, by the wheel of a truck oraircraft hitting the pressure control valve 11.

The collar 155 includes an increased diameter shoulder 169. Thisshoulder 169, as shown in FIG. 4, receives a locking ring 171 when thecollar 155 is raised to a position which disengages the lugs 161 fromthe flange 165. The locking ring 171 is maintained in an annular groovein the enlarged diameter portion 157 of the coupler 15. A pin 173 havinga reduced diameter camming portion 175 is mounted for axial movementwithin the enlarged diameter portion 157 of the coupler 15 and is biasedto extend below the face of the enlarged diameter portion 157 by aspring 177. When the coupler 15 is detached from the pit valve 17, thespring 177 moves the pin 173 to a position shown in FIG. 4 whichmaintains the locking ring 171 above the reduced diameter cammingportion 175 so that the locking ring 171 engages the shoulder 169holding the collar 155 in its raised position, and thereby holds thelugs 161 in their retracted position. This facilitates placement of thecollar 155 and the lugs 161 over the flange 165. When the coupler 15 isin position on the pit valve 17, the pin 173 contacts the flange 165raising the pin 173, as shown in FIG. 3, so that the reduced diametercamming portion 175 is adjacent the locking ring 171, allowing thelocking ring 171 to spring inwardly away from the shoulder 169 so thatthe collar 155 may be pressed downward to engage the lugs 161 onto theflange 165 as shown in FIG. 3.

Prior to latching of the coupler 15 to the pit valve 17, the poppetvalve 149 of the coupler 15 will be in its sealed position, as shown inFIG. 4, bearing against a first sealing surface 178 of a coupler sealingring 179 to prevent fluid from leaking from the coupler 15. The couplersealing ring 179 is axially moveable within a bore 181 in the enlargeddiameter portion 157 of the coupler 15, and is biased by a spring 183 sothat when the poppet valve 149 is in its closed configuration the poppetvalve 149 forces the coupler sealing ring 179 slightly into the body ofthe coupler 15 to provide a spring-biased seal with the poppet valve149. With the collar 155 firmly latching the lugs 161 about the flange165, the coupler sealing ring 179 is slightly spaced above the flange165, as shown in FIG. 3.

The enlarged diameter portion 157 of the coupler 15 includes an annulargroove 185 which receives a secondary sealing ring 187 best shown inFIGS. 6, 7 and 8. This secondary sealing ring 187 includes a sealingmember 189 which is designed to engage and seal against the flange 165.The secondary sealing ring 187 is sealed within the groove 185 by anO-ring 191 and is held within the groove 185 by a ring 193 which ispermanently attached to the enlarged diameter portion 157 by a series ofbolts 195. In addition the enlarged diameter portion 157 includes aplurality of bores 197, best shown in FIG. 7, each of which includes aspring 199 and a spring pin 201. The spring pin 201 engages thesecondary sealing ring 187 and under the bias of the spring 199 forcesthe secondary sealing ring 187 to extend beyond both the enlargeddiameter portion 157 and the sealing ring 179. It will be seen thereforethat the sealing ring 179 and the secondary sealing ring 187 areindependently mounted within the enlarged diameter portion 157 of thecoupler 15 and each of these sealing rings 179 and 187 are biased forextension below the enlarged diameter portion 157. The maximum extensionof the secondary sealing ring 187 is limited by the ring 193.

The secondary sealing ring 187 extends beyond the enlarged diameterportion 157 to a sufficient extent to allow the sealing member 189 tocontact and seal against the flange 165, as shown in FIG. 3, when thecoupler 15 and the pit valve 17 are initially coupled. Thus before thepoppet valve 149 of the coupler 15 is opened, the coupler 15 is sealedto the flange 165 by the secondary sealing ring 187.

Once the coupler 15 and pit valve 17 are coupled, the poppet valve 149of the coupler 15 may be opened by rotating the handle 147. This handle147, as shown in FIGS. 2 and 3, includes a lever 203 which is pinned toa link 205 which is likewise pinned to an arm 207 attached to the poppetvalve 149. When the handle 147 is rotated, the poppet valve 149 and thesealing ring 179 will be lowered together in sealed relationship until asecond sealing surface 209 of the sealing ring 179 contacts and sealsagainst the flange 165. Likewise, when the poppet valve 149 is beingclosed, prior to disconnection of the coupler 15 from the pit valve 17,the poppet valve 149 will raise the sealing ring 179 a short distanceinto the enlarged diameter portion 157, lifting the sealing surface 209from the flange 165. This movement of the poppet valve 149 into theenlarged diameter portion 157 would be extremely difficult if thepressure control valve 11 and control coupler 15 were full of fluid,since the main piston 31 of the pressure control valve 11 would beclosed during this movement and a fluid lock would exist between themain piston 31 and the seal of the poppet valve 149 against the sealingring 179. A relief valve 211 is therefore included in the pressureregulating valve 11 to bypass fluid through a small opening around themain valve 31. This pressure relief valve 211 includes a valve stem 213which contacts the upper extremity of the arm 207 of the poppet valve149 when the poppet valve 149 is near its closed position. The length ofthe valve stem 213 is selected so that, as soon as the poppet valve 149contacts the sealing surface 209, the pressure relief valve 211 willopen.

In addition to the cam 145, a second cam 215 is included on the handle147. This cam 215 bears against the top of the collar 155 when thehandle 147 is rotated to the position shown in FIG. 2, so that thecollar 155 may not be raised to release the control coupler 15 from thepit valve 17 until the handle 147 is rotated to close the poppet valve149. This prevents inadvertent spilling of fuel. In addition, the cam215 prevents turning of the handle 147 to open the poppet valve 149unless the collar 155 is fully depressed so that the poppet valve 149may not be opened until the coupler 15 is properly connected to the pitvalve 17.

The pit valve 17 includes a second poppet valve 217 which is axiallymoveable along a sleeve 219 and is biased by a spring 221 to closeagainst the mouth 223 of the hydrant 137. A sealing member 225 isincorporated in the poppet valve 217 to seal against the mouth 223.

Face to face contact of the poppet valves 149 and 217 allows opening ofthe poppet valve 217 against the bias of the spring 221 through rotationof the handle 147. It will be recognized that a fluid pressure existswithin the pit valve 17, it will be extremely difficult to lower thepoppet valve 217, without first pressurizing the inlet 27 of thepressure control valve 11 and the coupler valve 15. A pressureequalizing valve 225 is incorporated in the upper face of the poppetvalve 217 and includes a valve stem 227 which protrudes slightly beyondthe face of the poppet valve 217. An actuating pin 229 is mounted foraxial movement within the poppet valve 149 and is biased to a raisedposition by a spring 231. The upper extremity of this pin 229 is incontact with the lower extremity of the link 205. The link 205 includesa slot 233 which allows a limited degree of free movement between thelink 205 and a pin 235 which is used to connect the link 205 to thepoppet valve 149. It will therefore be seen that initial rotation of thelever 147 will displace the link 205 relative the poppet valve 149 sothat the pin 235 moves to the upper end of the slot 223. This motionallows the link 205 to depress the pin 229 and thereby open the pressureequalizing valve 225 prior to any movement of the poppet valve 149.

When the coupler 15 is initially placed on the pit valve 17 and thecollar 155 is depressed to lock the coupler 15 to the pit valve 17 thesecondary sealing ring 178 under the bias of springs 199 will sealagainst the flange 165. The coupler 15 and the pit valve 17 aretherefore fluidly sealed so that it is now possible to pressurize thecoupler 15 and inlet 27 of the pressure control valve 11. A one way flapvalve 237 is included within a recess 239 in the poppet valve 149, asshown in FIG. 3. This flap valve 237 is positioned above a series ofports 241 which connect the recess 239 to the lower face of the poppetvalve 149, as shown in FIG. 6. A recess 243 as shown in FIGS. 3 and 6fluidly connects the flap valve 237 with the pressure equalizing valve235. It will therefore be seen that when the pressure relief valve 225has been opened by action of the pin 229 fluid will flow from the pitvalve 17 through the pressure equalizing valve 225, recess 243 and flapvalve 237 to pressurize the coupler 15 and the inlet 27 of the pressurecontrol valve 11. It should be noted that prior to downward motion ofthe poppet valve 149 the sealing surface 209 is still spaced above theflange 165 so that any leakage of fluid between the faces of the poppetvalves 149 and 217 would leak from the valve were it not for the sealingof the secondary sealing ring 187.

After the handle 147 has completed its initial movement which ispermitted by the slot 233 in the link 205, continued rotation of thelever 147 causes the poppet valve 149 to continue lowering and tocontact the poppet valve 217 thereby forcing the poppet valve 217 open.Since the pressure above and below the poppet valves 149 and 217 isequal this lowering motion is readily accomplished.

When the pressure control valve 11 is to be removed from the pit valve17, the poppet valves 149 and 197 are closed by rotation of the handle147, as explained above. Until the collar 155 of the coupler 15 israised, the secondary sealing ring 187 maintains the seal between thecontrol valve 11 and the pit valve 17. With the poppet valve 197 closed,and the handle 147 rotated to the uncoupling position, the pressurerelief valve 191 will reduce the pressure in the inlet 27 of the controlvalve 11. If, however, the poppet valve 197 is faulty, so that fuelcontinues to flow, the control valve 11 remains pressurized, with thesecondary sealing ring 187 preventing spillage. If, with such a faultoccurring, the operator attempts to raise the collar 155 of the coupler15, the pressure forcing the control valve 11 away from the pit valve 17will prevent the lugs 161 from rotating, and will thus prohibit raisingof the collar 155 until the fault is remedied.

The pit valve 137 additionally incorporates a pair of flapper valves245, one of which is shown in FIG. 2, which are rotatably mounted on apair of concentric shafts 247 and 249. These shafts 247 and 249 areconnected to a pair of flanges 251 and 253, respectively, which rotatewith the shafts 247 and 249. A spring 225, best shown in FIG. 5, isattached to each of the flanges 251 and 253 to bias the flapper valves245 to a closed position. The flanges 251 and 253 each include anaperture 257 and 259, respectively which is aligned with a pin 261 whenthe flapper valves 245 are adjusted to their open position, as bymanipulating the tabs 263 and 265. The pin 261 is axially moveablewithin a sleeve 267 so that it may engage and disengage the apertures257 and 259 within the flanges 251 and 253. The pin 261 is biased towardthe flanges 251 and 253 by a spring 269 so that, once the pin 261 isengaged within the apertures 257 and 259, the spring 269 will maintainthe engagement. A link 271, shown in FIG. 2, is used to attach the pin261 to a lip 273 surrounding the collar 155 of the coupler 15. The link271 is pinned to the pin 261 and is biased to rotate toward the collar155 by a spring 275. The link 271 includes a hook 277 which engages thelip 273 so that, if the pressure control valve 11 is torn from the pitvalve 17 through an accident causing a failure of the lugs 161, themovement of the coupler 15 and the collar 155 away from the pit valve 17will raise the link 271 to disengage the pin 261 from the apertures 257and 259, automtically closing the flapper valves 245 under the action ofthe spring 255. The link 271 includes a rotatable camming lever 279which, when rotated (as shown in phantom lines in FIG. 2) rotates thelink 271 away from the lip 273 so that, during proper removal of thecontrol coupler 15 from the pit valve 17, the locking ring lip 273 willslide along a flat face 281, of the rotatable lever 279 and avoidengagement of the link 271 with the lip 273. When the control coupler 15is placed onto the pit valve 17, the upper surface of the hook 277 actsas a cam to rotate the link 271 to allow the lip 273 to pass beneath thehook 277.

It will be recognized that once the flapper valves 245 have closed,whether due to mechanical failure of the coupler 15 or for any otherreason, it will be extremely difficult to reopen the flapper valves 245so long as there is hydrant pressure below the valve. For this reason apressure equalizing valve has been included in one of the flapper valves245 as best shown in FIG. 9. This pressure regulating valve allowspressurization of the housing above the flapper valves 245 which in mostcircumstances will include only the pit valve housing 17 since thepoppet valve 217 will be closed. The pressure equalizing valve 283includes a sealing member such as an O-ring 285 positioned around a bolt287 which passes through a bore 289 in the flapper valve 245. The bolt287 is asserted into an actuating arm 291 which is connected to theshaft 247. It will be recognized that when the shaft 247 is rotated toclose the flapper valve 245 the sealing ring 285 will be compressedbetween the actuating arm 291 and the flapper valve 245 to seal the bore289. However, when it is desired to open the flapper valve 245, theshaft 247 is rotated so that the actuating arm 291 and its associatedbolt 287 are lowered from the flapper valve 245, thus engaging the seal285 from the bore 289 and allowing fluid to pass between the bolt 287and the bore 289 to pressurize the housing above the flapper valves 245.Continued rotation of the shaft 247 will then open the flapper valve245. A similar equalizing valve may be associated with each of the fibervalves 245 to allow pressure equalization when either of the actuatingarms 291 is rotated.

Referring now to FIG. 10 the details of the wheel assembly used fortransporting the pressure control valve may be explained. The wheels 21are mounted on casters 293 carried by legs 295 which rotate about a pin297 which is attached to the housing of the pressure control valve 11. Aspring 299 is used to bias the legs 295 to a retracted position as shownin phantom lines in FIG. 10. The wheels may be rotated by the operatorto the operating position shown in full lines in FIG. 10 at which pointa catch 301 which is pivotally mounted on a pin 303 attached to the leg295 will engage a bracket 305 attached to the pressure control valve 11.This catch 301 is biased by a spring 307 to maintain the engagement ofthe catch 301 with the bracket 305 and thus hold the legs 295 in theposition shown in full lines. The pressure control valve may now bewheeled to a position adjacent the pit valve 17. The operator may thendepress the catch 301 allowing the legs 295 to rotate to the positionshown in phantom lines under the action of the spring 299 thus allowingthe operator to lower the pressure control valve 11 onto the pit valve17.

It should be noted that in some circumstances it is advantageous todelete the catch 301 from the wheel assembly and to reverse the spring299 so that the spring 299 biases the legs 295 to the position shown infull lines in FIG. 10. The wheels 21 under the action of the spring 299will then partially support the weight of the pressure control valve 11and facilitate rolling of the pressure control valve 11 to a positionabove the pit valve 17. The operator in this configuration needs only todepress the pressure control valve 11 onto the pit valve 17 against thebias of the spring 299 so that the wheels 21 will ride on the pavement19 surrounding the pit valve 17 and will be raised to approximately theposition shown in phantom lines in FIG. 10. This latter arrangement ofthe spring 299 will additionally assist the operator in removing thepressure control 11 from the pit valve 17 since the bias of the spring299 will assist in lifting the pressure control valve 11 out of the pit.

FIGS. 11 and 12 show an alternate and improved embodiment of the coupler15 which is particularly adaptable for connecting the pressure controlvalve 11, or any other fluid conduit, to a hydrant 17 when the hydrant17 is arranged in an orientation other than that shown in FIGS. 1, 2 and3, that is, when the hydrant valve flange 165 of FIG. 4 is not directedvertically upward. As is explained previously in reference to FIGS. 3and 4, when the hydrant 17 is arranged in the orientation shown in FIG.1 the pressure control valve 11 may be readily lowered onto the hydrant17 and the collar 155 of the coupler 15 will normally drop due to itsown weight toward the hydrant 17, locking the lugs 161 in position oncethe pin 173 is moved to the position shown in FIG. 4 releasing thelocking ring 171. It will be immediately recognized, however, that thepressure control valve 11 or any other large fluid conduit which may beattached to the coupler 15 may be quite heavy. If the hydrant 17 isarranged in any orientation other than that shown in FIG. 1, theoperator, after placing the coupler 15 adjacent the hydrant 17, will berequired to displace the collar 155 toward the hydrant 17 in order tolock the lugs 161 around the hydrant flange 165. This is an exceedinglydifficult operation for one operator to accomplish, since he mustsupport the weight of the pressure control valve 11 or other fluidconduit during the depression of the collar 155. In order to alleviatethis difficulty the improved coupler 15 of FIGS. 11 and 12 may beutilized.

Like numerals are used in FIGS. 11 and 12 to identify those elements ofthis improved coupler 15 which are identical to the elements of FIGS. 1through 10. In this embodiment the locking ring 71 is designed to engagean annular groove 309, the upper edge of which forms a smooth transitionto the interior bore of the collar 155 in order to facilitatedisplacement of the locking ring 177 into the reduced diameter cammingportion 175 of the pin 173 when the collar 155 is displaced toward thehydrant 17.

Referring particularly to FIG. 12, the enlarged diameter portion 157 ofthe coupler 15 includes a pair of bores 311 exterior of the secondarysealing ring 187. Each of the bores 311 terminates in a reduced annularflange portion 313 which serves as a bearing for axial movement of a pinmember 315 having an enlarged head which bears on the upper extremity ofthe collar 155. Each of the pins 315 threadably engages a screw 317. Apair of springs 319 is biased between the head of the screws 317 and thereduced diameter flange 313 so that the pins 315 are biased to moveaxially within the bearing flanges 313 toward the hydrant 17 to whichthe coupler 15 is to be attached. It will thus be recognized that thepins 315 bias the collar 155 downward, as viewed in FIGS. 11 and 12, sothat when the pin 173 engages the hydrant valve flange 165 (FIG. 4),releasing the locking ring 171, the collar 155 will be displaced due tothe bias of the springs 319 toward the hydrant 17 to which the coupler15 is to be attached.

It will be appreciated, therefore, that the improved coupler 15 shown inFIGS. 11 and 12 facilitates easy attachment of a pressure control valve11 or other fluid conduit to a hydrant 17 regardless of the orientationof the hydrant 17. For example, if the hydrant 17 is positioned so thatits flange 165 faces vertically downward, the operator need only raiseand invert the coupler 15 and engage the coupler 15 against the flange165 of the coupler 17 to depress the pin 173 and the collar 155 willthen automatically move to engage the lugs 161 onto the hydrant valveflange 165. When the coupler 15 is to be removed from the hydrant 17,the operator need only pull the collar 155 away from the hydrant 17,releasing the lugs 161 and permitting the pin 173 to move to a positionwherein the locking ring 171 engages the groove 309 of the collar 155 tolock the collar 155 in its retracted position against the bias of thesprings 319.

What is claimed is:
 1. A pressure control valve for use in conjunctionwith a hydrant for controlling the downstream pressure of a fluidflowing from said hydrant, said hydrant having a poppet valve closingthe outlet of the hydrant, comprising:a main valve housing, including amain flow passage having an inlet and an outlet; coupler means forcoupling said inlet to the outlet of said hydrant; poppet valve means insaid housing for closing said inlet, said poppet valve means beingmounted to reciprocate away from said housing to open said inlet andshift said hydrant poppet valve to open the outlet of said hydrant;means on said housing for reciprocating said poppet valve means awayfrom said housing; means for sealing said poppet valve means to saidinlet when said poppet valve means closes said inlet; a main piston insaid housing, means for adjustably positioning said main piston withinsaid main flow passage to automatically precisely regulate the flow offluid therethrough, said piston being positionable to close said mainflow passage; and means on said housing for bypassing fluid around saidmain piston when said poppet valve means is positioned to close saidinlet, to avoid a fluid lock between said means for sealing said poppetvalve means and said main piston and thereby allow said reciprocatingmeans to engage said poppet valve means with said inlet.
 2. A pressurecontrol valve as defined in claim 1 wherein said sealing meansadditionally seals said inlet to said hydrant.
 3. A pressure controlvalve as defined in claim 1 wherein said bypassing means comprises:abypass valve mounted within said main valve housing, said valveincluding a valve stem which contacts said poppet valve means to opensaid bypass valve when said poppet valve means is positioned to closesaid inlet.
 4. A pressure control valve as defined in claim 3 whereinsaid bypass valve fluidly connects said inlet to said outlet when saidpoppet valve means is positioned to close said inlet.